UNIX domain socket -> INET socket ?

[Ronald F. Guilmette]

Two questions:

First, are UNIX domain sockets in any sense ``more efficient'' than
INET (IPv4) sockets?

Second, does there exist any freely available utility tool that would
allow one to connect up a UNIX domain socket to an INET domain socket,
e.g. so that the functionality of a program that talks only to UNIX
domain sockets could be made available over the Internet?